CVE-2021-46904

Multiple ttys try to claim the same the minor number causing a double unregistration of the same device. The first unregistration succeeds but the next one results in a null-ptr-deref.

The get_free_serial_index() function returns an available minor number but doesn't assign it immediately. The assignment is done by the caller later. But before this assignment, calls to get_free_serial_index() would return the same minor number.

Fix this by modifying get_free_serial_index to assign the minor number immediately after one is found to be and rename it to obtain_minor() to better reflect what it does. Similary, rename set_serial_by_index() to release_minor() and modify it to free up the minor number of the given hso_serial. Every obtain_minor() should have corresponding release_minor() call.

References

Affected packages

Git /

Affected ranges

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-46904.json"

unresolved_ranges

[
    {
        "events": [
            {
                "introduced": "2.6.27"
            },
            {
                "fixed": "4.4.268"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "4.5.0"
            },
            {
                "fixed": "4.9.268"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "4.10.0"
            },
            {
                "fixed": "4.14.232"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "4.15.0"
            },
            {
                "fixed": "4.19.187"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "4.20.0"
            },
            {
                "fixed": "5.4.112"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "5.5.0"
            },
            {
                "fixed": "5.10.30"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "5.11.0"
            },
            {
                "fixed": "5.11.14"
            }
        ]
    }
]